Heterocyclic nitrogenous cyanine dyes containing a new group added to the nitrogen atom thereof



Patented May 16, 1 950 HE'IEROGYCLIC NITRoGE'N'oUs DYES; CONTAINING A NEW GROUP ADDED TO THE'YN-ITROGEN ATOM THEREOF Alfred W. Anish, Vestal, N. Y.,.aSSiflOI to general Aniline & Film Corporatiom-NewYoi-ky N. Y., a corporationof Delaware No Drawing. 1 Original application September" 7,

1946, SeriaFNm 95,559. ni'viaea ar sings plication November 7, 1946; Serial No: 708,473

'7 Claims.

This invention relates to heterocyclic nitrogeneous cyanine dyes containing a new group attached to the nitrogen atom thereof; sensitizing dyes used with silver-halide emulsionsmust not only provide the desired sensitiyity, but must meet other requirements chief of which are non-diifusibility in the emulsion andsoluhllity'inliquids used for adding the dye to the-emulsion. A dyeselect'ed for its sensitizing power need not and usually does not have such other prerequisites:

It is known that-variations of the structure of a sensitizing dyele'adto changesin its sensitizingcharacteristics. Hence; if a dye be satisfact'ory from the standpoint of its sensitivity; but deficientfi'om the standpoint of solubilityor diff-'- fusibllity, and it is attempted to cure thed'efici'em cy by the introduction of substituents changing the dye molecule, a modification of the sensitizing characteristics necessarily ensues.

It is recognized in the art that the greater the molecular weight :o'fa product, the lower its solubility; discounting, of course, the presence of solubilizing groups. Hence; if-a sensitizing dye is deficient from the standpoint of diflusibility and satisfactory from the standpoint of solubility a change in the size ofthe molecule to cure the deficiency causes-alesseningof solubility.

It is also a truism that the characteristics of a cyanine dye will not vary greatly if the aliphatic atom grouping attached thereto is varied within limits. Thus; it'is possible to use interchangeably the low molecular'weightaliphatic radicals'rangmg: up to say i carbon atoms'without amateria'l modification of the properties of" the dye. How'- ev'er'. if this limit be exceeded to increase" the size and hence the non-diffusibility ofthe'dye' as a whole, then again we findtha't' the dye has undergone a markedde'part'u're in properties'from those of the original.

I have nowdiscovered that by'introducingone or two methylene groups between a p toluen'e sultonate group. and a nitrogenous heterocyclic system, compounds" are obtained which, when utilized as alkylating' or' quatern'izing agentsfor basic nitrogenous hetero'cyclic dye intermediates usually employed in thep'r'oduction of sensitizing dyes, yield dye salt intermediates which undergo the usual reactions for the preparationof'cyanine dyes. These dyes. are characterized not only by their speedandg-radation but also by non-diffusing properties in multilayer films without any sacrificeinsolubility; g

It is an object of the present invention to provid e anew class of heterocyclic nitrogenous cyanin'e dyes containing a new'grou'pattach'edto the nitrogen atoin thereof;

Other objectsiandadvantages of 'this'invention will become apparent? by reference to the follow 2- ing specification-in-whichitspreferreddetailsarid embodiments: are described.-

I'have found that when-an aromatic primary amino compound,v containing in addition a hydroxy; mercapto,-orselenyl'group in the-ortho position, is heated with-glycolic orhydracrylic acid, azoles' are obtained, which upon further treatment with p-toluenesulfonyl chloride, yield azole toluenesulfonic-acid resters; which are-excel lent-alkylating or= quaterniz-ing agents'for basic heterocyclic nitrogenous intermediates usually employed; in cyaninedyes. Y

The alkyla'ting or quaternizing agents prepared according to the present invention-are characterized bythe following;general formulaz R: wherein Rrepresentsfhydrogen; an aliphatic radical such as an alkylgroup; e. g.', methyl; ethyl. pro-p 11; butyl; a'n'dthe'like; alli'ox'y; e:' g., ethoxy. ethoxy'," propoxy; etc), halogen; ef g2, chlorine or bromine; or aniline" group; R1 represents either hydrogen, a halogen; or an aliphaticradical of the's'ame value "as R, R andR together represent a inethylenedioxy group, represents either hydrogen oran aliphatic "group of the "same vah'ie as R, X represents elther'oxygen; sulfur or selenium'; and n represents anumer'ai ranging fiom lto'2.

The aromaticprimaryemino compounds containing a hydroxy, mer'cap'to or selenylgroup in the ortho-position and'utilized asstarting"iilaiterialsf'or' the preparation of theabovealkyla'ting or quaternizing agents are represented "by the" fol lowing general forrnms:

wherein R, R1, Re, and Xhave the samevalues as-above.

As representative examples-of suitable compounds represented by. the above formula.(2) may. be mentioned": 2"-amino-phenol, 2 mins phenyl' mercaptan, 2-amino' phen'yl selenoiner} ca tan, 2 aniino 5-1nethoXyphenol; Z ainiiiO-S ethoxy pheri'yl' mercaptah; 2-'amino 4,5-dir'neth'- oXy-phenyl mercaptau, 2 ainino-5 aiiiliiio-'ph'ehy1 mercaptan, zamind-acmoro-pnenm 'mercaptah, 2-amino-4g5-niethylenedfoiiy-phenyl" mereaptan, 2-arnino-3-1methyl-phenyl niercapt'an; and the like.

In preparing" the: ua ter-sizing agents" of the present invention, a molecular equivalent of an aromatic primary amine represented by formula (2) is heated with a Slight excess of a molecular equivalent of glycolic or hydracrylic acid represented by the general formula:

HO (CH2) nCOOH wherein n represents a numeral ranging from 1 to 2, at a temperature ranging from 120-155 C., for several hours. The methods of isolating the resulting product vary with the nature of the aromatic primary amino compound and the organic acid employed in the condensation reaction. In the case where the reaction mixture consits of an orthoamino-phenyl mercaptan, or orthoamino-phenyl selenomercaptan and glycolic acid, the product is isolated by diluting the reaction mixture with water at room temperature, and a sufficient quantity of a mild oxidizing agent such as a 3% solution of hydrogen peroxide, aqueous solution of NaOH-potassium ferricyanide, sodium peroxide, sodium perborate, oxygen, etc., is added until a solid precipitate ensues. The purpose of the oxidizing agent is to-convert the unreacted phenyl mercaptan or phenyl selenomercaptan to the insoluble disulfide or diselenide. The precipitate is separated from the liquid portion of the reaction mixture, redissolved in a minimum amount of 3-N caustic soda solution, in which the Z-methylol azole is soluble, and the solution treated with a small quantity of charcoal, and the compound reprecipitated carefully by the addition of a solution of acetic acid. An additional fraction of the final product may be obtained from the filtrate by salting out with sodium chloride.

V Where the reaction mixture consists of an amino-phenyl mercaptan or amino-phenyl selenomercaptan, and hydracrylic acid, the unreacted portion of the amino-phenyl mercaptan, or amino-phenyl selenomercaptan, is extracted with a 4 to 10% solution of caustic soda in which the 'final product is insoluble, the extract rendered slightly acid, and the insoluble portion extracted with a water immiscible solvent such as ethyl ether, petroleum ether, benzene, and the like.

The residue remaining after distilling ofi the ether is then subjected to a fractional distillation. The distillate obtained above 150 C., and 2 mm; pressure is utilized in' the reaction with p-toluenesulfonyl chloride.

In the case where an aminophenol and glycolic or hydracrylic acid is used, the reaction mixture is extracted several times with ether, the extract dried with anhydrous sodium sulfate, and the ether distilled off. The oily residue remaining after distilling off the ether is subjected to a fractional distillation under reduced pressure. All

of the distillate obtained above 150 C., at 2-3 mm.

of pressure is mainly an alkylol benzoxazole, and

utilized as such in the reaction with the p-toluenesulfonyl chloride.

One mol of the product as above obtained is dissolved in a suificient quantity of 8-N caustic soda solution and the solution heated on a steam bath. To the hot solution, 1 mol of p-toluenesulionyl chloride is added and the mixture allowed to stand at room temperature for 2 or more hours. The precipitated product is recovered by filtration, washed with water, the solid dried in air, and recrystallized from petroleum ether.

When a molecular equivalent of Z-aminophenyl mercaptan is heated with a slight excess of a molecular equivalent of glycolic acid and the resulting 2-methylol-benzothiazole reacted with p-toluenesulfonyl chloride, two reactions occur which may be written as follows:

nooo-om-on NH:

The toluenesulfonic ester (0) so prepared is then reacted with any one of the nitrogenous heterocyclic bases, usually employed in the synthesis of cyanine dyes, in the known manner, such as by heating in a sealed tube at a temperature ranging from 65 to 150 C. Another method comprises heating said ester and base at about C., with a solvent-diluent, for a time sufficient for quaternization to take place.

The heterocyclic nitrogenous cyanine dye intermediates containing a new group attached to nitrogen atom thereof and prepared according to the present invention are characterized by the following general formula:

wherein R, R1, R2, X and n have the same values as in general formula (1), R3 represents a methyl group, and Y represents the atoms necessary to complete a five-membered or six-membered heterocyclic nitrogenous nucleus of the type usual in cyanine dyes such as benzoxazole, benzothiazole, benzoselenazole, indoline, indolenine, naphthoxazole, naphthiazole, oxazole, oxazoline, pyridine, quinoline, selenazole, selenazoline, thiazoline, thiodiazole, and the like.

The following examples describe in detail the method for preparing the quaternizing agents and cyanine dye intermediates quaternated with said agents, but it is to be understood that they are presented merely for the purpose of illustration and are not to be construed as limitative.

Example I Q-benzothiazolylmethyl p-toluenesulfonate Sixty grams of 2-amino phenyl mercaptan and 42 grams of glycolic acid were heated together at -155 0., for several hours. The mixture was poured into water at room temperature and 10 cc. of a 3% hydrogen peroxide solution added. The precipitate is separated from the liquid porhe Qtthe; r a m x red s re miglmum amount of 3-N caustic-soda soluttop and filtered; A sgnalL quantity of chareoat was; a ddeq, the product reprecipitated carefully hyagldition'of a 10% solution of acetic acid, and the; solid; product recoveredand dried.

Sixty grams of the product; as above obtainedis dissolved in 500 cc-. of Si -N caustie soda solution and the solutigr; heatgg on a steam bath. To the hotsqlution '70 grams of p-toluerresultouyl chloriqe'was added and the mixture allpweq to stand at room' temperature for seyera; hours.

The greipitated product was 60016 @tered, washer} with water, the solid dried in air, age recrystallized from petroleum ether;

Ezvample II fiz ieeee m p v e yxl r eleeeee l eeete Eourteen grams of Z-aminophenyl; mex'eemtal'r amt 11; grams of hydraoryl ic acid; were heatedtogetherat 149 455"- C;, for'twohours. The-gummy firoqujct, which is soluble in acid but insoluhle n; alkali; was eggtraeted; with a 5% solutionofi e austifc soda so as to remove any upreaoted zfle amine phenylmercaptan. The insoluble residue was extraeted several ttmes with ethyl ether agtgt he residue remaining afterd istilliug off the ether was subjectedto a fractional distillation above 1-50-- C1, and= at 2 mm. pressure. The die tiiiite obtained at1651-7Q-" at3 mm. pressure-, T

was a yellowishbrown oil; 7

The yellowish-brown oil qptained as above was then reacted with p-toluenesul ionyl, chloride in Eatample I.

' Example HI N 2-benzoxazoly1methyl p-toluggeeglfonate fifty-four grams of Z-amin pherryl mercaptarl 15 1% ram w ie ee i fwer sheetesls ti s'efiher e5 n es m e. I..- The. reaet qa a eafire te ev ra t mes. w th ethe and th n. em. w th 'nh r uasedium sul ate. Th 3s. 11 "renamin a r. dis il e a t pff l fi l w 1- pl f e iqnaL eieti letiee 1. 91?! refi e The. dist lla e attained; b ve 9 e 2;. raressuxe we 33%}?! 1 The Z-methylol benzoxazole as above obtained was then reacted with p-toluenesulfonyl chloride asin Example I.

Example IV me name 0t swaths} grams of 2-benzothiazolvlmethyl p-tolfuenesutionate were heated; a tube in an oil bath for 4 hours at 9- 'lzhgcrude solid was ground with an, ghee-acetone.. mixture, washed with acetone, arid nfmu (ag Eqe P eK geample VI v et a oil been me ranouraat see-.1632 Ga brown solid was ground ith ethereacetone-e m tu t finale w w with" ace dne fieeliemdeet' ew m s at 1W 6- Example V i! C-zCHI crude produc C-CH;

Five grams each of Z-methyl benzothiazole and 2-benzoxazolylmethyl p-toluenesulfonate were heated together in a. tube in an oil bath for 4-5 hours at 100 C. The crude solid was pulverized in an ether-acetone mixture and washed with acetone.

As. stated above, the preceding examples are merely illustrative of the use of .my new quaternizing agents. It is to be understood that such agents are effective as quaternizing agents for any heterocyclic nitrogenous dyestuff intermediate of-thetype useful in preparing cyanine dyes and irrespective of the chain length of the dyestufi, or grouping in 2-position to the nitrogen atom thereof.

Example IX Five-tenths grams each of 5-acetanilido-3-allylmethylene rhodanine and 2-methyl-3-(2-benzothlazolyl methyl) benzthiazole p-toluenesulfonate prepared according to Example IV'were dissolved in 15.000. of isopropyl alcohol and refluxed in the presence of 1.0 cc. of triethylaminefor 2 hours. The .dye was filtered off after cooling, and boiled out twice with alcohol. Its sensitizing speed in bromoiodideemulsions is 100% greater than that of a corresponding dye having an ethyl group attached to the nitrogen atom of the benzothiazole nucleus.

Example X o s s 0 mo o=oncn=on-o U o N 0 he. a. p

.bne each; of. Z-B-acetaniIldo I vinyl-5,6- methylene-dioxy benzothiazole ethiodide and 2- rnethyl-5,6rmethylenedioxy-3-(2 benzothiazolyl pared according to Example V were dissolved in 20.0 cc. of pyridine and 0.5 cc. of triethylamine added. The mixture was heated over stem for 1 hour, then cooled and filtered.

The residue on the filter was recrystallized twice from methyl alcohol. The dye sensitized a silver-bromoiodide emulsion to about; 680 m t, with a maximum at 640 mp.

Ezrample XI Five-tenths gram each of 2-,8-acetanilido vinyl benzoxazole ethiodide and 2-methyl-3-(2- benzothiazolyl methyl) benzothiazole p-toluenesulfonate prepared according to Example IV were heated in 15.0 cc. of pyridine in the presence of 0.5 gram of triethylamine at 100 C. for 15 minutes. The reaction mixture was cooled, diluted with an equal volume of water, and allowed to stand at room temperature. The dye crystals were filtered off, boiled out with two portions of methanol and then crystallized from ethanol. The dye sensitized a silver-.bromo-iodide emulsion to about 600 m with a maximum at 560 m and had a stronger sensitization in this type of emulsion than the corresponding dye wit ethyl groups on both nitrogen atoms.

Four and three-tenths grams of 2-;3-acetanilido vinyl benzoxazole ethiodide and 3.4 grams or 2 methyl 5,6 methy1ene-dioxy-3-(Z-benzothiazolyl methyl) benzothiazole p-toluenesulfonate prepared according to Example V were dissolved in 35.0 cc. of pyridine and 1.5 cc. of triethylamine added. The mixture was heated over steam for one hour. cooled and diluted liberally with water.

0 Ha I- The crystals which separated out were filtered oil and recrystallized from ethyl alcohol.

The dye sensitized a silver-bromoiodide emulniethyl) benzothiazole p toluenesultonate pre $1011 to 820 m with a maximum at 580 my.

Eliaml le .XIII

Two and six-tenths grams of 2-methyl-4-acet- 'anilido methylene-5-oxo-thiophene and 4.7 grams f Q-methyl-3-(2-benzothiazoly1 methyl) :henzothiazole p-toluenesulfonate prepared according to Example were dissolved :in 50.0 -.cc. of lsopropylalcohol and -0.5 cc. :of triethylamine added. The mixture was refluxed for 30 minutes, and then cooled and the dye filtered 01f.

Example XIV '1 Ease 0:1 JkCH-Tf 231E:

Three and nine-tenths grams 0'1 2-B-m'ethylmercapto vinyl benzothiazole ethiodide and 1.5 grams of 3-ethyl rhodanine were condensed by refluxing for 1 hour in 100 cc. of isopropylalcohol in the presence of 1.0 cc. of triethylamine. The dye which settled out on cooling was filtered off and reacted further without purification.

Two and five-tenths grams of the merocyanine thus prepared were alkylated with 3.0 cc. of methyl sulfate by heating together at 110 C. for minutes. The reaction product was cooled, chilled, and the excess of methyl sulfate decomposed by adding pyridine.

Three and six-tenths grams of 2-methyl-4,5- diphenyl-3-(2-benzothiazolyl methyl) thiazole ptoluenesulfonate :prepared according to Example' VI were added and the'mix'ture heated at 140 C. for minutes. The rhodacarbocyanine dye was isolated by boiling the crude reaction product with dioxane to remove impurities and then recrystallized from methyl alcohol. The dye sensitized color film strongly with a maximum at 640 mu.

Three grams each of 2-B-acetanilido vinyl- 5,6-dimethyl benzoxazole ethiodide and 2-methy1- 3-(2-benzothiazolyl methyl) benzothiazole ptoluenesulfonate prepared according to Example IV were dissolved in 90.0 cc. of pyridine to which 0.5 cc. of triethylamine was added and the mixture heated on a steam bath for 15 minutes. The reaction mixture was cooled and diluted with an equal volume of water and allowed to stand at room temperature. The dye crystals were filtered off and recrystallized twice from ethyl alcohol. The dye sensitized a silver-bromoiodide emulsion to 600 m n, with a maximum at 565 mm.

"In color emulsion compositions, this dye had "a'speed Bil-400% greater than the corresponding dyewith an ethyl group attached to the benzo- "thiazole nucleus.

Example .XVI

Four and eight-tenths grams of 2-methyl-3-(2- benzothiazolyl methyl) benzothiazole p-toluenesulfonate prepared according to Example VII and 2.0 grams of 3-allyl-5-acetanildo methylene .rhodanine were dissolved in 150.0 cc. of isopropyl alcohol and heated to reflux on a steam bath in the presence-oi 0.5 cc. of triethylamine. The dye which separated was filtered-01f and boiled *out with methyl alcohol. The sensitization data was similar to that of the dye described in Example The sensitization of photographic silverbromoiod-ide emulsion was more powerful than that of an identical dye with ethyl on the nitrogen atom of the benzothiazole nucleus.

Four and eight-tenthsgrams of 2-methyl-3- "(z-benzothia'zolyl methyl) benzo'thiazole ptoluenesu'lfonateprepared according to Example IV and 3.5 grams of '2-methylmercapto-6- methyl quinoline ethiodide were dissolved in 100.0

attain Example XVIII- One and one-half grams of p-dimethylamino -benzaldehyde and 4.8 grams of 2-methyl-3(2- benzothiazolyl methyl) benzothiazole p-toluenesulfonate prepared according to Example IV were dissolved in 30.0 cc. of pyridine and the mix ture heated at an oil bath temperature measuring 110 C., for 40 minutes. The dye which formed precipitated out upon dilution'with water. The dye crystals were recrystallized from methyl alcohol and have an absorption maximum in alcoholic solution at about 555 m Example XIlI was repeated with the exception that an equivalent quantity of 2-methyl-3-(2- benzothiazolyl methyl) benzothiazole p-toluenesulfonate, prepared according to Example VIII,

'was substituted for 2-methyl-3-(2-benzoxazolyl methylene) benzothiazole p-toluenesulfonate.

dye increased the light sensitivity of a photographic emulsion considerably more than the corresponding dye with an ethyl group attached to the nitrogen atom.

While the foregoing dye salts have been prepared in the form of the preferred iodide, it is clearly apparent that they can also be prepared like, containing the monoand polymethine dyestuffs of the present invention, it isonly necessary to disperse the dyestuffs in the emulsions. It is convenient to add the compounds from solutions in appropriate solvents. An alcohol, such as methanol or ethanol, is satisfactory as asolvent for the dyestuffs.

- Emulsions prepared in accordance with this invention can be coated in the usual manner upon any desired support, such as cellulose nitrate,

cellulose acetate, polyvinyl acetal resin, .glass,.

paper, and the like.

The concentration of these new dyestufls in the emulsion can vary widely, i. e., ,from about 1 to about 100 mg. per liter of flowable emulsion. The concentration of the dyestufi' will vary accordin to the type of light-sensitive material in the emulsion and according to the eflect desired. The suitable and most economical concentration for any given emulsion will be apparent to those skilled in the art upon making the ordinary tests and observations customarily used in the art of emulsion making.

The cyanine dye intermediates prepared in accordance with the'present invention are not only useful for the preparation of cyanine dyes, but also as supersensitizing agents for photographic emulsions. In actual practice only a very small amount is added to the emulsion just prior to coating to obtain supersensitizing properties. The actual amount employed varies but on the average 3-10 mgs. are added in solution to 100 cc. of photographic emulsion containing sensitizing dyes.

This application is a division of my co-pending application Serial No. 695,559, filed September '7, 1946, now United States Patent 2,453,738.

While there have been pointed out above certain preferred embodiments of the invention, the same is not limited to the foregoingexamples, illustrations or to the specific details given therein, but is capable of variations and modifications as to the reactants, proportions and conditions employed. Accordingly, it is intended that the invention be defined only by the accompanying claims, in which it is intended to include all features of patentable novelty residing therein.

I claim:

l. A cyanine dye in which at least 1 nucleus attached to the methine chain is selected from the class consisting of those of the following general formulae:

and

anion and G-membered heterocyclic nitrogenous nuclei and 5-membered keto-heterocyclic nucleusof the type usual in cyanine dyes, R represents a member selected from the class consistingof hydrogen, halogen, aliphatic, and anilino groups, R represents a member selected from the class consisting of hydrogen, halogen, and aliphatic groups, R and R1 together represent a methylenedioxy group, R2 represents a member selected from the class consisting of hydrogen and aliphatic groups, X represents a member selected from the class consisting of oxygen, sulfur, and selenium, Y represents the atoms necessary to complete a heterocyclic nitrogenous nucleus of the type useful in cyanine dyes, and n represents a numeral ranging from 1 to 2.

2. A cyanine dye in which at least 1 nucleus attached to the methine chain has the following formula:

wherein A represents a methine chain of from 1 to 4 carbon atoms linked to a nuclear carbon atom of a member of the group consisting of 5- "and 6-membered heterocyclic nitrogenous nuclei and 5-membered keto-heterocyclic nucleus of the type usual in cyanine dyes, and Y represents the atoms necessary to complete a heterocyclic nitrogenous nucleus of the type useful in cyanlne dyes.

attached to the methine chain has the following formula:

wherein A represents a methine chain of from 1 to 4 carbon atoms linked to a nuclear carbon atom of a member of the group consisting of 5- and B-membered heterocyclic nitrogenous nuclei and 5-membered keto-heterocyclic nucleus of the type usual in cyanine dyes, and Y represents the atoms necessary to complete a heterocyclic nitro'genous nucleus of the type useful in 'cyanine yes.

4. A cyanine dye in which at least 1 nucleus attached to the methine chain has the following formula:

3. A cyanine dye in which at least 1 nucleus 14 wherein A represents a methine chain of from 1 to 4 carbon atoms linked to a nuclear carbon atom of a member of the group consisting of 5- and G-membered heterocyclic nitrogenous nuclei 5 and 5-membered keto-heterocyclic nucleus of the type usual in cyanine dyes, and Y represents the atoms necessary to complete a heterocyclic nitaigigenous nucleus of the type useful in cyanine l0 5. A cyanine dye characterized by the following formula:

6. A cyanine dye characterized by the following formula:

c .cn-cn=o--s (3H0 EI/ can 40 7. A cyanine dye characterized by the following formula: 

1. A CYANINE DYE IN WHICH AT LEAST 1 NUCLEUS ATTACHED TO THE METHINE CHAIN IS SELECTED FROM THE CLASS CONSISTING OF THOSE OF THE FOLLOWING GENERAL FORMULAE: 